The invention relates to a spring hinge for eyewear enabling the temples of eyeglasses to be opened beyond the regular position of use according to claim 1.
From patent EP 90 107 388 are known spring hinges allowing for the temples of eyewear to be opened beyond the regular position of use and which are intended for use with the temples of eyeglasses. Such a spring hinge is provided with a locking element having a U-shaped cross section. The U-shaped locking element consists of a first and a second leg and presents a projection on the first of its legs on its free side and toward the outside. The locking element is lodged in a sliding element and in a first recess of the sliding element in such a manner that its two legs point away from the axis of the hinge. The projection of the locking element abuts in a spring-loaded manner with the shoulder of a second recess, thus constituting a stop for a spring plunger.
Furthermore, from GB-2 248 121 A is known a spring hinge for eyewear, in which a cylindrical locking element is provided with a circular shoulder. The locking element in GB-2 248 121 is diametrically divided by a slot. The shoulder engages in a recess provided in the temple of the glasses.
A disadvantage of such a design of the spring hinge is that the locking effect of the locking element can be obtained only by a spring resistance acting upon the locking element since the locking element is spread by the spring itself or by a spring plunger. A further disadvantage is that a spring guide pin must preload the required spring to ensure that the locking effect is attained. In turn, this has the disadvantage that the assembly is relatively costly and difficult.